A crystalline lens of an eye is shaped like a biconvex lens and is very elastic. When a ciliary muscle contracts, a suspensory ligament relaxes, and the crystalline lens bulges using its own elasticity, to shorten a focal distance and change a diopter; therefore, the eye can clearly view an object at a near distance. When the eye views an object at a far distance, the ciliary muscle relaxes, and the crystalline lens is in a flat state at this time. If the eye views an object at a near distance for a long time, a ciliary body is in a contracted and strained state for a long time and cannot get enough rest. As a result, the eye may feel fatigue, sore, or painful, or a qualitative change that is difficult to recover may even occur in the crystalline lens, causing refractive errors such as nearsightedness. However, during daily usage of eyes, people spend a lot of time viewing objects at a near distance, for example, reading a book, writing, or viewing various screens (such as screens of a television, a computer, a tablet computer, and a mobile phone), and usually forget to or do not have time to frequently look into the distance and protect vision by letting the ciliary muscle relax for a while.
In prior arts, for example, Taiwan Patent Publication No. TW201012448A, various methods for helping people protect vision are recorded. For example, a panel capable of sliding forward and backward is used, so that people continually adjust focal distances of crystalline lenses of eyes when gazing at the panel, thereby achieving the objective of exercising the eyes. For another example, a fatigue degree of eyes is monitored, and when it is found that the eyes are fatigue, an alarm signal is automatically sent, requesting a user to exercise eyes. All these technologies require interruption of an action such as work or study being currently performed by a user to dedicatedly exercise eyes, and require dedicated eye exercise devices. Some of the devices are difficult to carry and have bad user experience. Therefore, an apparatus and a method which can protect vision of eyes without affecting a business being currently dealt with by a user need be found.